cytokinins defined in 1951 yearcytokinins - cytokinins (phytokinins);
cytokinins - Group of plant hormones recognized (and named) because of stimulatory effect on division of plant cells. Effect requires presence of auxin. Chemically identified as purines; first one discovered, kinetin, was isolated from DNA preparations from yeast and from animal tissues, Zeatin occurs in sweet corn kernels. Substances with similar physiological action occur in some plant tissues (fruitlets, coconut milk and other liquid endosperms); also isolated from micro-organisms causing plant tumours, witches brooms and from the infected tissues themselves. Cytokinins influence other aspects of plant growth, e.g. promote cell enlargement and seed germination, stimulate bud formation, delay senescence, counteract apical dominance. Effects believed to be associated with increase in nucleic acid metabolism and protein synthesis. Question of transport in plants not yet resolved. See also: Auxins, Hormone, Gibberellins.
near cytokinins in Knolik
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